Duggar Sisters Jana, Jill, Jessa and Jinger Pen Relationship Book

"It's not always easy to get along with 18 siblings," four of the Duggar siblings write in their new book, Growing Up Duggar)

We figured as much. The four eldest daughters of the famously large Duggar clan from TLC's hit reality show 19 Kids & Counting share their insights in a new book, Growing Up Duggar, which will hit stores March 4.

Jana, 24, Jill, 22, Jessa, 21, and Jinger, 20, write about how their Christian beliefs influence all their relationships – with themselves, their siblings, their parents, their friends, their pop culture interests (the Internet, movies and music), their country (getting involved in politics), the world (doing charity work), and, yes, even guys.

Last year, Jessa began a courtship with Ben Seewald of Hot Springs, Ark., which will be featured on the next season of the show, set to premiere April 1.

The young Duggar women also detail in the book the difference between dating and courtship, and why they believe it is important to get to know how young men they are interested in react in "normal family settings."

"We want to get acquainted with a young man in a normal family setting, where we'll be watching how he treats our brothers and sisters," they write. "We want to see how he reacts to normal family events, such as Josie accidentally spilling her milk in his lap, Jackson unintentionally ruining his board game or Joseph trouncing him in a basketball match."

Jana, Jill, Jessa and Jinger also focus on self-esteem and how important it is to "accept the girl in the mirror."

Though they admit there are arguments at home, the sisters write about the importance of sincere apologies and working together.

Last June, when Jessa began her courtship, the girls had finished penning the book, and mom Michelle shared her thoughts on watching her daughter during this time.

"It is sweet as a mom to watch Jessa go through this," Michelle told PEOPLE. "She and Ben are open to encourage others who may be considering relationships that you can stay morally pure and wait for the one God has for you and then on your wedding day, begin the physical aspects of your relationship."